I'm cheap, so I wouldn't bother buying a new one. You'll have to do some painting regardless of which you do, unless you find an oem bumper that happens to be white.
You've already bought it and fiberglass is cheap, I'd start with that route. If it doesn't work for you, you can get a new bumper. Make sure you trim up the bumper before you start the fiberglassing, you want to fix the cause before the band-aid goes on.
I got a new shell, just need to stop driving the DX so I can work on it.
I've got a filter for my mouth, it just isn't a good one.